package sword;

/**
 * @Author: 海琳琦
 * @Date: 2022/5/27 20:43
 * https://leetcode.cn/problems/er-cha-shu-de-zui-jin-gong-gong-zu-xian-lcof/
 */
public class Title68II {

    class TreeNode{
        int val;

        TreeNode left;

        TreeNode right;

        public TreeNode(int val) {
            this.val = val;
        }
    }

    /**
     * p、q最近公共祖先
     * @param root
     * @param p
     * @param q
     * @return
     */
    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
        if (root == null || root == p || root == q) {
            return root;
        }
        TreeNode left = lowestCommonAncestor(root.left, p, q);
        TreeNode right = lowestCommonAncestor(root.right, p, q);
        if (left != null && right != null) {
            return root;
        } else if (left == null) {
            return right;
        } else {
            return left;
        }
    }


}
